Auto insurance comparisonAuto insurance comparisonUninsured motorist insurance coverage protects the driver and passengers in the event of a traffic accident caused by another driver — especially if that driver does not have auto insurance. Of course, the law currently requires drivers to have auto insurance. But that doesn’t mean every road user follows the rules. So this protection is an important addition to your policy. The same goes for underinsured motorist coverage. This coverage is needed if the at-fault driver has insufficient liability limits.
UM and UIM are similar in purpose but are not identical types of coverage. The first applies to accidents involving a completely uninsured driver. The second applies when the at-fault driver has insurance, but their limits are insufficient to cover the damages. Requirements for these coverages vary by state, and the specific terms are set by the policy.
The CivilCarCoverage insurance portal helps drivers compare and evaluate offers from licensed insurance partners before selecting a policy. We are not an insurance company ourselves, but we help car owners in the U.S. determine protection.
UM is designed for accidents caused by drivers who have no liability insurance. Instead of relying solely on the at-fault driver to pay for your losses, you may receive compensation through your own policy if it includes this protection. Put simply, Uninsured motorist coverage explained means protecting yourself against the financial consequences of another driver's failure to carry insurance.
So, what does uninsured motorist cover? UM primarily helps pay for injuries to you and your passengers after an accident caused by an uninsured driver. Depending on state law and policy terms, property damage may also be covered through Uninsured Motorist Property Damage (UMPD). However, this option is not available on the same terms in every state.
In some cases, UM may also apply to hit-and-run accidents when the responsible driver cannot be identified. Rules vary by state and may include evidence requirements, police reporting, and other restrictions. Always check your policy and local regulations.
Underinsured motorist insurance is coverage that helps in cases where the at-fault driver in an accident has liability insurance, but the limits are insufficient. Underinsured motorist insurance is coverage that helps when the at-fault driver has liability insurance, but the limits are insufficient — for example, when a serious accident results in significant medical expenses or lost income, and the at-fault driver’s coverage does not fully cover these costs.
In this situation, UIM coverage allows you to recover a portion of the remaining losses after the at-fault driver’s insurance has been applied. This coverage typically applies to bodily injury. However, property damage coverage may also be available. This depends on state law and the specific policy. The definition of insufficient insurance coverage, the calculation method, and the terms of payment may also vary.
It is important to remember, however, that UIM does not guarantee that your own insurer will automatically pay the entire difference between your losses and the other party’s payout. You should take into account the established limits, rules for coordinating payments, policy terms, and the circumstances of the accident. Before purchasing a policy, it’s worth checking whether it provides coverage for bodily injury, property damage, or both.
The main difference between Uninsured and Underinsured motorist coverage is whether the at-fault driver has liability insurance and whether their limits are sufficient.
UM applies when the responsible driver has no insurance. UIM helps when they are insured but cannot fully cover the injured party's losses. Together, these options form underinsured uninsured motorist coverage, providing protection in both situations.
There are also two important distinctions:
Both UM and UIM may pay expenses related to physical injuries. The covered costs and payment limits depend on the policy.
This helps pay for damage to a vehicle or other property. It may be available under UM or UIM, depending on state law and contract terms. Not every state offers the same options.
UM/UIM should not be confused with liability insurance coverage. Liability pays for certain losses you cause to others. UM/UIM helps protect you when the responsible driver cannot provide sufficient compensation.
Learn more about other protection options in our guide to types of car insurance coverage.
Requirements for UM/UIM coverage in the U.S. depend on the laws of each individual state. In some states, this coverage is mandatory, while in others, drivers can decide for themselves whether to include it in their policy. Sometimes the insurer is required to offer the coverage, but the customer has the right to decline it, usually in writing.
Therefore, when checking the minimum coverage requirements, it’s important to clarify the rules for UM and UIM separately. They may differ even within the same state. A requirement for one type of coverage does not necessarily apply to the other.
If the law allows for a waiver, the insurance company may ask you to sign an uninsured motorist rejection form. However, before signing, you should verify exactly which type of coverage you are waiving: compensation for bodily injury, property damage, or both types of losses. After all, a signed document could affect your ability to receive an insurance payout following a traffic accident.
For local rules, visit car insurance requirements by state. You can also read Uninsured Motorist Coverage Laws: What States Require by Law for more details.
To explain uninsured motorist coverage simply, it helps protect you when the driver responsible for an accident cannot pay for your losses. Understanding “how does uninsured motorist coverage work” starts with the general claims process.
If an uninsured driver causes an accident, you can report it to your insurer when you have UM protection. The company reviews the incident, supporting documents, and damages. It then determines whether your policy provides compensation.
For UIM, the process is similar, but the responsible driver has insurance with insufficient limits. You should inform your insurer about the claim against the other driver's provider and follow the procedures in your contract.
An uninsured or underinsured motorist claim usually requires proof of the other driver's responsibility, the amount of damage, available limits, and payments made or expected from the at-fault party's insurer.
Requirements vary by state and policy. Keep photos from the accident scene, witness contact details, police reports, medical records, and correspondence with insurers.
For more information, see How Does an Uninsured Motorist Claim Process Work?
Even if UM/UIM is optional in your state, consider how an accident involving an uninsured or underinsured driver could affect your finances.
To answer “how much uninsured motorist coverage do i need”, review these factors:
We explain how to determine the optimal amount of insurance coverage and what factors to consider when making your choice in the article “How Much Uninsured Motorist Coverage Do You Need?”
Stacked coverage deserves special attention — a mechanism that, under certain conditions, allows you to combine the UM/UIM coverage limits for multiple vehicles or policies. This enables a driver to obtain a higher total coverage limit. However, the possibility of such a combination depends on state law and the terms of the specific policy.
Our guide to Stacked vs unstacked uninsured motorist explains how these options differ, how they may affect available limits, and what to check before buying a policy.
When considering auto insurance uninsured motorist protection, start by reviewing your current policy. Check whether UM and UIM are included, what limits apply, and which expenses are covered. Then compare other offers against your needs.
CivilCarCoverage can help with this process. We are neither an insurance company nor an agency, but our service helps users explore and compare available options. Complete the online form to start your search.
Stacked coverage allows, under certain circumstances, the UM/UIM limits for multiple vehicles or insurance policies to be combined, thereby increasing the available coverage. In contrast, unstacked coverage does not allow for such a combination: the insurance limits apply separately. The applicability of each option and the method for calculating compensation are determined by state law and the terms of the specific policy.
For details, read Stacked vs. Unstacked Uninsured Motorist Coverage Explained.
